Magnetic disk drives that are widespread in use as storage devices for image data and the like, including the external storage devices of computer systems, are required to be higher in recording density, larger in capacity, and more compact. To achieve a higher recording density, a larger capacity, and more compactness, it is effective to raise linear recording density by minimizing the distance between the magnetic head slider and the magnetic disk, that is, the flying height of the magnetic head slider. In recent years, magnetic head sliders adjustable in flying height by mounting a heater in the neighborhood of a read/write element have been developed and this, in turn, has made it possible to reduce the flying height of the read/write element, even when there are changes in operating environment.
A magnetic head slider adjustable in flying height is disclosed in Japanese Patent Publication No. 2005-056447 (“Patent Document 1”), for example. Patent Document 1 also discloses a configuration in which the heater and the read/write element are surrounded with a resin film of low rigidity to make only the neighborhood of the heater and the read/write element project deform.
Japanese Patent Publication No. 2003-099910 (“Patent Document 2”) discloses a magnetic head slider configuration in which, an intermediate stepped face deeper than a stepped bearing surface and higher than a negative-pressure grooved face is provided between the stepped bearing surface and the negative-pressure grooved face, on the pad located at the trailing end of the magnetic head slider, in order to prevent the lubricant accumulated on the slider from coming into contact with a magnetic disk surface and consequently causing the slider to vibrate, even when the flying height, that is, the clearance between the magnetic head slider and the magnetic disk surface, is narrowed.
For a magnetic head slider that controls the flying height of the read element or write element of a magnetic head by using thermal expansion due to the heat from a heater, the flying height of the head element on the slider is likely to become a minimum. Accordingly, if the head element comes into contact with a magnetic disk, frictional force due to the meniscus force, van der Waals force, or other force caused by the lubricant on the magnetic disk during such contact may vibrate the head slider, resulting in the head element being worn or damaged. Particularly for a head element inferior in read/write characteristics, since reducing the flying height by conducting height control using thermal expansion is preferable for read/write operations, a risk of the head element wear or damage correspondingly increases. In addition, when a perpendicular magnetic recording medium is combined with such a magnetic head slider, the recording medium, compared with a longitudinal magnetic medium, does not require a texture that assigns magnetic anisotropy. It is preferable in terms of flying performance, therefore, that surface roughness be reduced to its minimum. Therefore, the surface roughness of the perpendicular magnetic recording medium is set to be up to 0.3 nm in centerline average roughness “Ra”. There is the problem, however, that as the surface roughness of the perpendicular magnetic recording medium becomes less significant, the magnetic head slider vibrates more easily since, as discussed above, larger frictional force is caused by contact of the slider with the magnetic disk.
Patent Documents 1 and 2 above, relating to the respective magnetic head sliders that control the flying height of the read element or write element of the magnetic head by using thermal expansion due to the heat from the heater, do not describe alleviating the frictional force caused by contact of the head element with the magnetic disk, or preventing the vibration of the slider due to the frictional force.
Furthermore, for a magnetic head slider that controls the flying height of a head element by using thermal expansion due to heat from a heater, since the flying height of the head element becomes a minimum, if the head element comes into contact with a magnetic disk, the frictional force occurring during the contact may vibrate the slider, resulting in head element wear and/or damage.